When a circularly polarized antenna is operated in close proximity to a ground plane, such as the surface of a body of water, energy radiated from the antenna array is reflected by the ground plane and may result in destructive interference. Performance characteristics of the antenna system, such as axial ratio and circular polarization (CP) gain, are negatively impacted by such interference.
Antenna systems for use on the surface of a body of water may be deployed from ships, submarines, or airplanes. It is generally desired that the antenna systems stowed on board take up as little volume as possible. Moreover, it may be desired that the volume occupied by antenna arrays during operation near a ground plane be minimized, for example, in order to avoid detection by unauthorized persons. Furthermore, it may be costly to retrieve such antenna systems, once deployed in the sea.
There exists a need for an antenna system with improved performance characteristics when operated in close proximity to a ground plane. It is further desired that such an antenna system occupy a suitably low volume and that the system be cost-efficient enough for expendable use.